This invention relates generally to plastic bottle or container constructions, and particularly to thin walled bottles or containers which are collapsible and foldable, as well as to a process and apparatus for collapsing such bottles or containers.
In the container industry, there are a number of known applications for relatively thin, flexible bottles or containers, some of the more well known of which relate to the shipment and retail sale of beverages such as milk, water, juice, etc., as well as liquid or powdered cleaners, detergents and the like.
It is often the case that such containers must be shipped over considerable distances to distributors who fill and then ship the filled containers to retail concerns. During the initial shipment to distributors, the empty containers, for example one gallon containers, take up so much space that, from a volume standpoint, the manufacturer is shipping mostly air.
At the same time, there is great concern in the environmental arena for plastic materials which for the most part are not biodegradable, and which therefore pose significant disposal problems, particularly in light of the ever expanding utilization of plastics in virtually every area of technology. The problem is especially acute in the container industry.
This invention seeks to alleviate both of the above described concerns by:
1) providing a plastic bottle or container construction which requires approximately one half of the plastic currently used in most plastic containers, particularly those which typically carry milk, water, juice, detergents (liquid or powder) and other liquids and/or particulates; and
2) shaping the containers in such a way as to facilitate collapse and folding to a compact size which results in a four or more to one increase in shipping capacity.
For purposes of this invention, the term "container" refers to plastic containers or bottles having shapes as disclosed herein. In accordance with a preferred embodiment of the invention, a thin walled plastic container is manufactured by an extrusion or injection blow molding process, incorporating a thin walled construction which permits the normally self-supporting container to be collapsed and a portion or portions concentrically folded to provide a compact, nestable and/or stackable container for efficient shipment.
The container side wall in a preferred embodiment is provided with peripheral, vertically spaced steps or shoulders which facilitate axial collapse and subsequent concentric folding of portions of the side wall to provide a collapsed and folded container article with at least four "layers" of side wall arranged in a zig-zag or S-shaped configuration, in generally surrounding relationship to tapered shoulder and narrow neck portions of the container.
The container side wall may also be formed originally with one or more steps, or with a smooth, tapered or even straight peripheral side wall and nevertheless collapsed and folded as will be explained further herein.
A plurality of containers collapsed and folded in the manner described above may be arranged in the form of a stack for easy and efficient shipment.
There is also disclosed for eventual use with the preferred embodiment of the invention a relatively rigid open-topped pitcher for receiving and holding the plastic container. The pitcher is formed with interior beads and/or steps about its periphery, which are designed to engage the corresponding steps or shoulders on the container side wall to thereby hold the container in place during pouring.
An exemplary embodiment of an apparatus utilized to carry out the collapsing and folding operation includes a container holder and reciprocable fluid actuated tool members which act in sequence to form first and second folded portions of the container. More specifically, one exemplary embodiment of the apparatus includes a container holder device, opposing elements of which are reciprocable between open and closed positions, and adapted to hold or support a container during a collapsing and folding operation. The holder is mounted on a supporting surface provided with an opening through which an associated container may be brought into position. The supporting surface is also provided with one or more stops for limiting downward movement of a container-engaging tool element as described in greater detail below.
The apparatus also includes a tool frame comprising a stationary platen supported on a plurality of columns in vertical alignment with the container holder device. The stationary platen mounts a main double acting cylinder assembly. A lower piston rod portion (which is of tubular construction) extends through the stationary platen and is secured to an inner container-engaging pusher member. An outer container engaging pusher member or sleeve is concentrically located relative to the inner pusher member and is held in resilient spaced relationship thereto by guide bars and a pair of side cylinder assemblies, the cylinders of which are secured to the inner pusher member and the piston rods of which are secured to the outer pusher member.
The inner pusher member includes a movable upper platen provided with a substantially cylindrical lower portion having a tapered annular surface which is adapted to engage the tapered shoulder portion of the container.
The outer pusher member or sleeve includes a movable lower platen provided with an annular skirt portion movable in telescoping relationship with the cylindrical lower portion of the inner pusher member. The lower edge of the depending skirt portion is adapted to engage the container sidewall as further described herein.
The lower movable platen is adapted to engage the one or more stops provided on the supporting surface to limit downward movement of the outer pusher member, while the lower movable platen itself serves as a stop to limit the relative downward movement of the inner pusher member and its associated upper movable platen.
An upper tubular piston rod portion of the main double acting cylinder is fixedly secured at its distal end to a lower horizontal element of an open rectangular frame. A top cylinder assembly is fixedly secured to an upper horizontal element of the open rectangular frame, with the piston of the top cylinder extending through the upper frame element and connected to an upper side of a pancake cylinder assembly, so that the pancake cylinder assembly is reciprocable within the open rectangular frame, independent of the main cylinder. The lower side of the pancake cylinder assembly mounts an air adaptor manifold (including an air inlet and an outlet) which in turn is connected to an air tube which extends downwardly through the tubular main piston and through the stationary, upper and lower platens to a recessed area within the center of the inner pusher member. At the same time, the pancake cylinder has a small diameter rod attached to (or integral with) its own piston rod which extends downwardly through and below the lower end of the air tube.
The lower end of the tube is fixed to an upper washer or bushing and the lower end of the rod is fixed to a lower washer or bushing. Between the two washers or bushings, there is located a resilient, expandable plug, shaped and sized to fit within the discharge opening of a container. The lower bushing also is provided with apertures for introducing air from the air tube to the interior of the container, and for exhausting air from the container during the collapsing and folding operation.
The operation of the above described apparatus is explained briefly below, and in more detail further herein.
Initially, a series of containers may be fed, one at a time, on a conveyor or the like structure to a location beneath an aperture provided within the supporting surface of a work table. At this location, lateral movement of the containers may be halted and the main cylinder assembly actuated to move the inner and outer pusher members to their downwardmost position, along with the open rectangular frame and associated pancake cylinder and top cylinder. Once the components are in their fully lowered position, the top cylinder is actuated to extend the pancake cylinder and tube and rod members to a loading position where the resilient plug is located below the work table. In a fully automated system, the downward movement of the plug would terminate with the plug located in the discharge opening of the container. In a semi-automatic system, the container may be loaded manually onto the plug. The pancake cylinder itself is then actuated to retract the rod, thereby pulling the lower bushing upwardly relative to the upper bushing to thereby force the resilient plug to expand radially outwardly to simultaneously grip the container and seal the discharge opening thereof. Thereafter, the top cylinder is retracted to draw the container upwardly into the aperture provided in the work table, and the main cylinder is then actuated to draw the inner and outer pusher members, along with the plug and attached container, upwardly so that all components are in their upwardmost position and the container is situated immediately above the supporting surface.
The container holder device is then closed to provide support for the container and to hold the latter in precise alignment during the collapsing and folding operation. In this position, the lower edge of the outer pusher member is located closely adjacent or in engagement with, an intermediate one of the three annular steps on the container side wall.
Air at very low pressure is then introduced into the interior of the container through the tube extending from the resilient plug to the air manifold at the pancake cylinder assembly. This insures that the container will be in a normal fully blown condition with no creases or wrinkles which might otherwise interfere with the collapsing/folding operation.
The air manifold is then opened to permit the controlled escape of air from the container as the deforming operation commences. At this time, the main cylinder is actuated to move the inner and outer pusher members downwardly while the pair of side cylinders maintain a predetermined distance between the upper and lower movable platens of the inner and outer pusher members, respectively. In other words, the side cylinders act as springs, biasing the inner and outer pushers apart. In a preferred embodiment, the outer pusher member engages and pushes downwardly on the intermediate step on the peripheral wall of the container and initiates a first fold which is completed when the lower movable platen abuts the limit stops provided on the supporting surface of the work table. Continued downward movement of the lower piston portion of the main cylinder overcomes the side cylinder forces tending to keep the upper and lower platens apart, so that the inner pusher member engages the shoulder portion of the container, pushing it downwardly to initiate a second folded portion in the peripheral side wall of the container, radially inward and adjacent the first folded portion. This second folded portion is completed when the upper movable platen abuts the lower movable platen.
If desired, the collapsing/folding operation may be terminated at this stage and, upon opening (or retraction) of the container holder and extension of the top cylinder piston, the container is pushed downwardly away from the inner and outer pusher members, and the pancake cylinder may again be actuated to extend the rod and lower bushing downwardly, thereby causing the resilient plug to contract, enabling the completed container to be removed from the apparatus.
In an alternative arrangement, upon completion of the first and second folds by the inner and outer pusher members, and prior to the extension of the pancake cylinder piston, the top cylinder may be actuated to partially extend its piston to thereby push the resilient plug downwardly, thereby also pushing the discharge portion of the container downwardly within the confines of the first and second folds so that the discharge opening does not extend above the uppermost edge of the folded portions. Following opening of the container holder, further extension of the top cylinder and extension of the pancake cylinder rod would then enable removal of the container in the manner described above.
Thus, in one aspect, the present invention relates to a collapsed thin wall container for facilitating compact shipment of a plurality of such containers comprising a bottom wall, a peripheral side wall extending from said bottom wall, a tapered shoulder section extending from the peripheral side wall, and a reduced diameter neck portion including a discharge opening extending from the tapered shoulder section, and the peripheral side wall including at least one portion folded outwardly and upwardly to form a first concentric folded portion extending upwardly at least to the tapered shoulder section.
In another aspect, the present invention relates to a stack of containers of the type described above.
In a related aspect, the present invention relates to a thin walled normally self-supporting flexible container of unitary construction having a bottom wall, a peripheral side wall, and a top wall which may include a tapered shoulder section and a reduced diameter neck portion provided with a discharge opening, the improvement comprising a plurality of vertically spaced annular steps formed in the side wall, each step causing the peripheral side wall portion immediately above the step to have a smaller diameter than the peripheral side wall portion immediately below the step, the steps adapted to permit the container to be collapsed and folded to a compact configuration wherein a pair of concentric folded peripheral side wall portions lie radially adjacent each other and adjacent the tapered shoulder and reduced neck portions of the container.
In another aspect, the present invention relates to an apparatus for collapsing and folding an upright container comprising, broadly, means for supporting and holding the container in an upright position; first forming means for engaging and exerting a downward force on the intermediate annular stepped portion for effecting the formation of a first folded portion; and second forming means for engaging and exerting a downward force on the tapered shoulder portion for effecting the formation of a second folded portion.
Finally, the present invention relates to a method of forming a collapsed and folded container broadly comprising the steps of:
a) providing a normally self-supporting, flexible container of unitary construction and having a bottom wall, a peripheral side wall extending from the bottom wall and a top wall which may include a tapered shoulder section extending from the peripheral side wall, and a reduced diameter neck portion extending from the tapered shoulder portion and including a discharge opening;
b) forming a first folded portion by pushing a first portion of the peripheral side wall downwardly toward the bottom wall; and
c) forming a second folded portion by pushing the tapered shoulder section downwardly toward the bottom wall after the completion of step b).
It will be understood that the container itself may have a different shape than that described above. For example, the container top wall may be flat, with a smaller or larger discharge opening therein. In this case, the described method and apparatus would be modified accordingly.
From the above, it will be appreciated that the present invention provides significant benefits in terms of shipping and storage capacity and efficiency while, at the same time, provides for substantial savings in the amount of plastic used in the manufacture of plastic containers, the latter having a further beneficial effect in the matter of waste disposal.
Other objects and advantages of the invention will become apparent from the detailed description which follows.